The field of electrosurgery is well known; see for instance, Palanker U.S. Pat. No. 7,238,185 and Palanker, et al. U.S. Pat. No. 6,780,178 both incorporated herein in their entireties. Briefly, application of a voltage to an electrode is useful for cutting, ablating and fulgurating biological tissue. This is generally known as electrosurgery. Typically the voltage is applied as a train of high frequency pulses in the radio frequency (RF) range to a probe in contact with the tissue.
A problem with electrosurgery is preventing excessive application of heat to the tissue being cut, fulgurated, desiccated, etc. since this tends to produce undesirable affects such as charring and collateral tissue damage. This is typically caused by high temperatures induced by, the application of the electrical energy.
Some highly localized high temperature is required during, for instance, tissue coagulation (sealing) for denaturation of blood and vascular tissue (veins and arteries) followed by occlusions of the blood vessels. Typically desiccation occurs below or close to 100° C. and fulguration at higher temperatures above 100° C. A high temperature during fulguration outside the immediate area being treated results in undesirable tissue charring and buildup of debris on the electrosurgical probe, which decreases its efficiency of coagulation. This may also result in adhesion of charred tissue to the probe and damage to the areas of the probe with low melting temperatures such as plastic components. Typically this might require cleaning of the probe after each session of coagulation. Also, high temperature may result in smoke obscuring the surgical field, especially for laparoscopic procedures.